how do you comfort someone who is grieving?

Just be there for her, that is your primary duty as a friend. Watch her closely and respond appropriatly to what she does. If she wants to talk about her mom, do it with her. If she wants to not talk, do that. Whatever she wants to do be there to accompany/assist her.

If you have lost your mother, you might talk about how you dealt with it, but pay close attention and be sure she is liking that convo...otherwise drop it for now.

The best thing that you need to do for her is to be there for her. Let her know that she will always have someone to talk to and that she has a shoulder for her to cry on. I am so sorry for your friend. If she wants to talk about her mother, give her a listening ear. If she doesn't want to talk about her mother, don't bring the subject up. She is grieving right now and she needs all the support that she can get.

What you can also do is take her out to the movies, shopping, have lunch; just try and do something fun so that she can be distracted temporarily. All you can do is be there for her. She will really appreciate that. Good luck.

Im so sorry for your friend. I don't know if there is much more you can do for her. Just keep being a great friend and lend your shoulder to her when she just wants to cry. and just be sympathetic.

Some times you can do more with just letting some one cry on you then trying to say something.